JPS5897815A - Repairing method for electric winding - Google Patents

Abstract

PURPOSE:To recover the insulation performance easily and in a short time without removing a coil from the main body such as a motor by a method wherein an injection port of an injector such as a syringe is inserted into a clearance in the insulation-deteriorated coil, then fluid insulator is injected, and accordingly the injected fluid insulator is soldified. CONSTITUTION:In a state that the insulation-deteriorated coil 2 is incorporated in the main body, the injection port 10 of the injector 9 is inserted into the clearance between insulators in the coil 2, and, while exhausting, by an exhaust device as the injector 9, from the opposite side, varnish is injected as the fluid insulator. When the varnish is exhausted from the exhaust side, the injection is finished. Next, the injection and exhaust ports are sealed, thereafter the entire motor is covered with a heat resisting sheet, the hot wind of 100 deg.C or more is sent into the inside of the cover, and accordingly the injected fluid insulator is solidified. The heating can be omitted according to the solidification characteristic of the insulator. Regarding the required time, two persons take 20hr to inject and further 12hr to solidify it.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for repairing electrical windings of motors, generators, etc., for easily restoring insulation when the insulation has deteriorated due to long-term use.

As electrical windings (hereinafter simply referred to as coils) are used over time, the insulation itself shrinks over time, and the performance gradually decreases due to the effects of electromagnetic force, heat, etc. At this stage, the coil insulation is replaced with a new one, or the entire motor, such as the motor, is refurbished.

When rewinding the coil insulation, remove the coil by disassembling the main body, repair the defective part, or rewind the coil. Such repairs require a large amount of man-hours and time and are not efficient. In addition, it is not economical to purchase a new main body, and especially if a large electric motor or the like is newly purchased, the burden will increase significantly. Therefore, if you do not have a spare machine and cannot get a new one, you will be forced to suspend operations during the repair period, which will reduce productivity and operating rates.

The present invention was created as a result of detailed investigation into the state of insulation deterioration in coils with deteriorated insulation, such as those used in large electric motors. The purpose is to inject the material and then solidify it.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view showing an example of a state in which a coil is installed in an electric motor, and 1 is a casing and 2 is a coil. Figure 2 shows one turn of the coil 2, 6 is a terminal,
F indicates iron core. FIG. 3 is an enlarged perspective view of the cross section taken along line AA' in FIG.

The coil 2 has a wire insulation 5 surrounding the wire 4, and a mica tape 6, a bias tape 7, and a glass tape 8 are wound thereon in this order. When insulators such as the mica tape 6 and the bias tape 7 are used for many years, their thickness decreases due to age deterioration, and a gap is created between them and the element wire insulation 5 due to this decrease in thickness. In this case, the electromagnetic force generated by the current flowing through the coil 2 causes the coils to move together or between the coil 2 and the iron core (
(not shown) is promoted, mechanical destructive force is applied to the entire insulator, and the cracks form eyes or turn into powder, which makes them more likely to absorb moisture, further deteriorating the insulation performance. .

If the insulation performance falls below a predetermined value, the product must be discontinued and repaired, but conventional repair methods include:
Perform cleaning phenol treatment to restore surface insulation. Alternatively, it is known to rewind the coil insulation. Cleaning pheno treatment cannot fill the gaps inside the insulation. Furthermore, the method of rewinding the coil insulation requires equipment to be shut down because the coil is disassembled, and requires a long repair time.

The present invention focuses on the above-mentioned gap that occurs within the coil, and actively utilizes this gap to easily restore insulation performance in a short time without removing the coil from the main body of the motor etc. It is something.

In the present invention, an injector such as a syringe is inserted into the gap in the coil where the insulation has deteriorated, a fluid insulating material is injected, and the injected fluid insulating material is solidified. After solidification, it is ready for use.

At this time, by removing gas such as air existing in the gap in advance, the powdered insulator can be removed at the same time, and this evacuation can be performed continuously while the fluid insulator is being injected from the opposite side to the injection side. This creates negative pressure within the gap, allowing effective injection.

As the fluid insulating material, it is preferable to appropriately select and use festivals, resins, etc. that solidify within a predetermined time after injection.

Next, the present invention will be explained in detail.

Table 1 shows the electric motor (250KW) that has been used for about a year.

3.3 KV', 1165 rl) m induction motor)
An example of repairing a stator coil according to the present invention is shown.

Table 1 Coil 2 with deteriorated insulation still installed in the main body (
(Fig. 1), insert the injection port 10 of the injection device 9 into the gap between the insulators in the coil 2 (Fig. 3), and while evacuating the injection device 9 from the opposite side with an exhaust device 11 similar to the injection device 9, the fluidized insulating material is This is an example of injecting pheno.

Injection was considered complete when pheno was discharged to the exhaust side.

Next, the injection port and the exhaust port were sealed, and then the entire motor was covered with a heat-resistant sheet, and hot air of 100° C. or higher was sent into the cover to solidify the injected fluid insulating material. Note that heating may be omitted depending on the solidification characteristics of the insulating material.

It took two people to pour the mixture, and it took 12 hours for it to solidify.

When the conventional q-coil rewinding method is implemented, it takes about 216 hours based on actual results, which shows how efficient the present invention is.

As can be seen from Table 1, the performance of the insulation resistance, dielectric loss (tan δ), and surge current vibration tests was significantly recovered after implementing the present invention. This is an industrially useful invention that allows the coils of electric motors, etc., to be easily repaired in a single hour.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing an example of the installed state of the motor stator side coil, Fig. 2 is an explanatory view showing one winding of the coil, and Fig. 3 is the same as Fig. 2. It is a perspective view which expanded the A-, A' cross section. 2; Coil 4; Cable line 9; Injector 10; Inlet

Claims (1)

[Claims] A method for repairing an electrical winding, the method comprising injecting a fluid insulating material into an insulation gap of an electrical winding whose insulation has deteriorated using an injection machine, and then solidifying the material.